Method and apparatus for supporting bandwidth part based operations in sidelink communication

ABSTRACT

Disclosed are methods and apparatuses for supporting BWP-based operations in sidelink communication. An operation method of a first terminal in a communication system includes receiving, from a base station, configuration information of a mapping relationship between an uplink (UL) bandwidth part (BWP) and a sidelink (SL) BWP; when a UL switching operation for the UL BWP is performed, performing an SL switching operation for the SL BWP mapped to the UL BWP based on the mapping relationship without separate signaling indicating execution of the SL switching operation; and performing sidelink communication with a second terminal in a switched SL BWP.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Korean Patent Applications No.10-2020-0058579 filed on May 15, 2020, No. 10-2020-0073097 filed on Jun.16, 2020, No. 10-2020-0099287 filed on Aug. 7, 2020, and No.10-2021-0053131 filed on Apr. 23, 2021 with the Korean IntellectualProperty Office (KIPO), the entire contents of which are herebyincorporated by reference.

BACKGROUND 1. Technical Field

The present disclosure relates to a sidelink communication technique ina communication system, and more specifically, to a technique forsupporting operations based on multiple bandwidth parts (BWPs).

2. Description of Related Art

The communication system (e.g., a new radio (NR) communication system)using a higher frequency band (e.g., a frequency band of 6 GHz or above)than a frequency band (e.g., a frequency band of 6 GHz or below) of thelong term evolution (LTE) communication system (or, LTE-A communicationsystem) is being considered for processing of soaring wireless data. TheNR system may support not only a frequency band of 6 GHz or below, butalso a frequency band of 6 GHz or above, and may support variouscommunication services and scenarios compared to the LTE system. Inaddition, requirements of the NR system may include enhanced MobileBroadBand (eMBB), Ultra Reliable Low Latency Communication (URLLC), andMassive Machine Type Communication (mMTC).

Sidelink communication may be performed in the NR system. The sidelinkcommunication may be performed using one or more bandwidth parts (BWPs).For example, sidelink signals and/or data may be transmitted andreceived within a BWP configured for sidelink communication. In order tosupport this operation, there is a need for methods for supportingBWP-based operations in sidelink communication.

SUMMARY

Accordingly, exemplary embodiments of the present disclosure aredirected to providing methods and apparatuses for supporting operationsbased on multiple bandwidth parts (BWPs) in sidelink communication.

According to a first exemplary embodiment of the present disclosure, anoperation method of a first terminal in a communication system maycomprise: receiving, from a base station, configuration information of amapping relationship between an uplink (UL) bandwidth part (BWP) and asidelink (SL) BWP; when a UL switching operation for the UL BWP isperformed, performing an SL switching operation for the SL BWP mapped tothe UL BWP based on the mapping relationship without separate signalingindicating execution of the SL switching operation; and performingsidelink communication with a second terminal in a switched SL BWP.

The configuration information may be included in system information or aterminal-specific radio resource control (RRC) message transmitted fromthe base station.

The same subcarrier spacing (SCS) may be applied to the UL BWP and theSL BWP having the mapping relationship.

When an SL resource is configured within a switched UL BWP, the SLresource may be configured after a preconfigured time from a completiontime of the UL switching operation to ensure UL transmission in theswitched UL BWP.

When an SL resource is configured within a switched UL BWP, the SLresource may be configured from a completion time of the UL switchingoperation, and an SL resource configured until a preconfigured time fromthe completion time of the UL switching operation may be ignored toensure UL transmission in the switched UL BWP.

When an SL resource is configured independently of a UL resource, thesidelink communication in the switched SL BWP and uplink communicationin a switched UL BWP may be simultaneously performed.

When an SL resource is configured independently of a UL resource, theuplink communication may be preferentially performed from the completiontime of the UL switching operation to a preconfigured time (e.g.,preconfigured duration) to ensure the uplink communication.

The operation method may further comprise, when an activation operationfor the UL is performed, performing an activation operation for the SLBWP mapped to the UL BWP based on the mapping relationship.

The operation method may further comprise, when a deactivation operationfor the UL BWP is performed, performing a deactivation operation for theSL BWP mapped to the UL BWP based on the mapping relationship.

An SL resource pool may be configured based on a reference BWP, and whena first numerology of the reference BWP is different from a secondnumerology of the SL BWP, the SL resource pool may be applied to the SLBWP in consideration of a ratio between the first numerology and thesecond numerology.

According to a second exemplary embodiment of the present disclosure, anoperation method of a base station in a communication system maycomprise: configuring a mapping relationship between an uplink (UL)bandwidth part (BWP) and a sidelink (SL) BWP; transmitting configurationinformation of the mapping relationship to a terminal; performing a ULswitching operation for the UL BWP; and performing uplink communicationwith the terminal in a switched UL BWP, wherein an SL switchingoperation for the SL BWP is triggered by performing the UL switchingoperation.

The configuration information may be included in system information or aterminal-specific radio resource control (RRC) message transmitted fromthe base station.

The same subcarrier spacing (SCS) may be applied to the UL BWP and theSL BWP having the mapping relationship.

When an SL resource is configured within a switched UL BWP, the SLresource may be configured after a preconfigured time from a completiontime of the UL switching operation to ensure UL transmission in theswitched UL BWP.

According to a third exemplary embodiment of the present disclosure, anoperation method of a first terminal in a communication system maycomprise: generating sidelink control information (SCI) including afirst indicator indicating execution of a sidelink (SL) switchingoperation of an SL bandwidth part (BWP); transmitting the SCI to asecond terminal; performing the SL switching operation based on thefirst indicator included in the SCI; and performing sidelinkcommunication with the second terminal in a switched SL BWP.

The operation method further comprise, when the sidelink communicationis performed based on a mode 1, receiving downlink control information(DCI) including the first indicator from a base station.

When the sidelink communication is performed based on a mode 2, whetherto perform the SL switching operation may be autonomously determined bythe first terminal.

The SCI further may include a slot offset, and the slot offset may be anoffset between a slot in which the SCI is transmitted and a slot inwhich the sidelink communication associated with the SCI is performed.

The SCI may further include a subchannel offset, and the subchanneloffset may be an offset between a subchannel in which the SCI istransmitted and a first subchannel in which the sidelink communicationassociated with the SCI is performed.

The operation method may further comprise receiving an offset indicatingan execution time of the SL switching operation from the base station,wherein the SL switching operation may be performed in a slot after theoffset from a slot in which the SCI is received.

An SL resource pool may be configured based on a reference BWP, and whena first numerology of the reference BWP is different from a secondnumerology of the SL BWP, the SL resource pool may be applied to the SLBWP in consideration of a ratio between the first numerology and thesecond numerology.

According to the present disclosure, a mapping relationship between ULBWP and SL BWP may be configured, and when a switching operation (oractivation operation or deactivation operation) of a UL BWP isperformed, a corresponding switching operation (or activation operationor deactivation operation) of an SL BWP mapped to the UL BWP may beperformed without separate signaling. Alternatively, the switchingoperation (or activation operation or deactivation operation) of the SLBWP may be performed by separate signaling. According to theabove-described operations, sidelink communication may be efficientlyperformed in the SL BWP.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram illustrating a first exemplary embodimentof a communication system.

FIG. 2 is a block diagram illustrating a first exemplary embodiment of acommunication node constituting a communication system.

FIG. 3 is a conceptual diagram illustrating a first exemplary embodimentof a type 1 frame.

FIG. 4 is a conceptual diagram illustrating a first exemplary embodimentof a type 2 frame.

FIG. 5 is a conceptual diagram illustrating a first exemplary embodimentof a transmission method of SS/PBCH block in a communication system.

FIG. 6 is a conceptual diagram illustrating a first exemplary embodimentof an SS/PBCH block in a communication system.

FIG. 7 is a conceptual diagram illustrating a second exemplaryembodiment of a method of transmitting SS/PBCH blocks in a communicationsystem.

FIG. 8A is a conceptual diagram illustrating an RMSI CORESET mappingpattern #1 in a communication system.

FIG. 8B is a conceptual diagram illustrating an RMSI CORESET mappingpattern #2 in a communication system.

FIG. 8C is a conceptual diagram illustrating an RMSI CORESET mappingpattern #3 in a communication system.

FIG. 9 is a conceptual diagram illustrating exemplary embodiments of amethod for multiplexing a control channel and a data channel in sidelinkcommunication.

FIG. 10 is a conceptual diagram illustrating a first exemplaryembodiment of a communication method according to Case 1.

FIG. 11 is a conceptual diagram illustrating a first exemplaryembodiment of a communication method according to Case 3.

FIG. 12 is a conceptual diagram illustrating a first exemplaryembodiment of different BWPs to which the same SL resource poolconfiguration is applied.

FIG. 13 is a conceptual diagram illustrating a first exemplaryembodiment of a method of configuring an SL resource pool in adjacentcell(s) and out-of-coverage terminal(s).

FIG. 14 is a conceptual diagram illustrating a second exemplaryembodiment of a method of configuring an SL resource pool in adjacentcell(s) and out-of-coverage terminal(s).

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present disclosure are disclosed herein. However,specific structural and functional details disclosed herein are merelyrepresentative for purposes of describing embodiments of the presentdisclosure. Thus, embodiments of the present disclosure may be embodiedin many alternate forms and should not be construed as limited toembodiments of the present disclosure set forth herein.

Accordingly, while the present disclosure is capable of variousmodifications and alternative forms, specific embodiments thereof areshown by way of example in the drawings and will herein be described indetail. It should be understood, however, that there is no intent tolimit the present disclosure to the particular forms disclosed, but onthe contrary, the present disclosure is to cover all modifications,equivalents, and alternatives falling within the spirit and scope of thepresent disclosure. Like numbers refer to like elements throughout thedescription of the figures.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present disclosure. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(i.e., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including,” when usedherein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this present disclosure belongs.It will be further understood that terms, such as those defined incommonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand will not be interpreted in an idealized or overly formal senseunless expressly so defined herein.

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in greater detail with reference to the accompanying drawings.In order to facilitate general understanding in describing the presentdisclosure, the same components in the drawings are denoted with thesame reference signs, and repeated description thereof will be omitted.

A communication system to which exemplary embodiments according to thepresent disclosure are applied will be described. The communicationsystem to which the exemplary embodiments according to the presentdisclosure are applied is not limited to the contents described below,and the exemplary embodiments according to the present disclosure may beapplied to various communication systems. Here, the communication systemmay be used in the same sense as a communication network.

FIG. 1 is a conceptual diagram illustrating a first exemplary embodimentof a communication system.

As shown in FIG. 1 , a communication system 100 may comprise a pluralityof communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2,130-3, 130-4, 130-5, and 130-6. Also, the communication system 100 mayfurther comprise a core network (e.g., a serving gateway (S-GW), apacket data network (PDN) gateway (P-GW), and a mobility managemententity (MME)). When the communication system 100 is a 5G communicationsystem (e.g., new radio (NR) system), the core network may include anaccess and mobility management function (AMF), a user plane function(UPF), a session management function (SMF), and the like.

The plurality of communication nodes 110 to 130 may support acommunication protocol defined by the 3rd generation partnership project(3GPP) specifications (e.g., LTE communication protocol, LTE-Acommunication protocol, NR communication protocol, or the like). Theplurality of communication nodes 110 to 130 may support code divisionmultiple access (CDMA) technology, wideband CDMA (WCDMA) technology,time division multiple access (TDMA) technology, frequency divisionmultiple access (FDMA) technology, orthogonal frequency divisionmultiplexing (OFDM) technology, filtered OFDM technology, cyclic prefixOFDM (CP-OFDM) technology, discrete Fourier transform-spread-OFDM(DFT-s-OFDM) technology, orthogonal frequency division multiple access(OFDMA) technology, single carrier FDMA (SC-FDMA) technology,non-orthogonal multiple access (NOMA) technology, generalized frequencydivision multiplexing (GFDM) technology, filter band multi-carrier(FBMC) technology, universal filtered multi-carrier (UFMC) technology,space division multiple access (SDMA) technology, or the like. Each ofthe plurality of communication nodes may have the following structure.

FIG. 2 is a block diagram illustrating a first exemplary embodiment of acommunication node constituting a communication system.

Referring to FIG. 2 , a communication node 200 may comprise at least oneprocessor 210, a memory 220, and a transceiver 230 connected to thenetwork for performing communications. Also, the communication node 200may further comprise an input interface device 240, an output interfacedevice 250, a storage device 260, and the like. Each component includedin the communication node 200 may communicate with each other asconnected through a bus 270.

However, each component included in the communication node 200 may notbe connected to the common bus 270 but may be connected to the processor210 via an individual interface or a separate bus. For example, theprocessor 210 may be connected to at least one of the memory 220, thetransceiver 230, the input interface device 240, the output interfacedevice 250 and the storage device 260 via a dedicated interface.

The processor 210 may execute a program stored in at least one of thememory 220 and the storage device 260. The processor 210 may refer to acentral processing unit (CPU), a graphics processing unit (GPU), or adedicated processor on which methods in accordance with embodiments ofthe present disclosure are performed. Each of the memory 220 and thestorage device 260 may be constituted by at least one of a volatilestorage medium and a non-volatile storage medium. For example, thememory 220 may comprise at least one of read-only memory (ROM) andrandom access memory (RAM).

Referring again to FIG. 1 , the communication system 100 may comprise aplurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2, and aplurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6.Each of the first base station 110-1, the second base station 110-2, andthe third base station 110-3 may form a macro cell, and each of thefourth base station 120-1 and the fifth base station 120-2 may form asmall cell. The fourth base station 120-1, the third terminal 130-3, andthe fourth terminal 130-4 may belong to cell coverage of the first basestation 110-1. Also, the second terminal 130-2, the fourth terminal130-4, and the fifth terminal 130-5 may belong to cell coverage of thesecond base station 110-2. Also, the fifth base station 120-2, thefourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal130-6 may belong to cell coverage of the third base station 110-3. Also,the first terminal 130-1 may belong to cell coverage of the fourth basestation 120-1, and the sixth terminal 130-6 may belong to cell coverageof the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1,and 120-2 may refer to a Node-B (NB), a evolved Node-B (eNB), a gNB, anadvanced base station (ABS), a high reliability-base station (HR-BS), abase transceiver station (BTS), a radio base station, a radiotransceiver, an access point, an access node, a radio access station(RAS), a mobile multihop relay-base station (MMR-BS), a relay station(RS), an advanced relay station (ARS), a high reliability-relay station(HR-RS), a home NodeB (HNB), a home eNodeB (HeNB), a road side unit(RSU), a radio remote head (RRH), a transmission point (TP), atransmission and reception point (TRP), or the like.

Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5,and 130-6 may refer to a user equipment (UE), a terminal equipment (TE),an advanced mobile station (AMS), a high reliability-mobile station(HR-MS), a terminal, an access terminal, a mobile terminal, a station, asubscriber station, a mobile station, a portable subscriber station, anode, a device, an on-board unit (OBU), or the like.

Meanwhile, each of the plurality of base stations 110-1, 110-2, 110-3,120-1, and 120-2 may operate in the same frequency band or in differentfrequency bands. The plurality of base stations 110-1, 110-2, 110-3,120-1, and 120-2 may be connected to each other via an ideal backhaul ora non-ideal backhaul, and exchange information with each other via theideal or non-ideal backhaul. Also, each of the plurality of basestations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to thecore network through the ideal or non-ideal backhaul. Each of theplurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 maytransmit a signal received from the core network to the correspondingterminal 130-1, 130-2, 130-3, 130-4, 130-5, or 130-6, and transmit asignal received from the corresponding terminal 130-1, 130-2, 130-3,130-4, 130-5, or 130-6 to the core network.

Also, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1,and 120-2 may support a multi-input multi-output (MIMO) transmission(e.g., a single-user MIMO (SU-MIMO), a multi-user MIMO (MU-MIMO), amassive MIMO, or the like), a coordinated multipoint (CoMP)transmission, a carrier aggregation (CA) transmission, a transmission inunlicensed band, device-to-device (D2D) communication (or, proximityservices (ProSe)), Internet of Things (IoT) communications, dualconnectivity (DC), or the like. Here, each of the plurality of terminals130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 may perform operationscorresponding to the operations of the plurality of base stations 110-1,110-2, 110-3, 120-1, and 120-2 (i.e., the operations supported by theplurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2). Forexample, the second base station 110-2 may transmit a signal to thefourth terminal 130-4 in the SU-MIMO manner, and the fourth terminal130-4 may receive the signal from the second base station 110-2 in theSU-MIMO manner. Alternatively, the second base station 110-2 maytransmit a signal to the fourth terminal 130-4 and fifth terminal 130-5in the MU-MIMO manner, and the fourth terminal 130-4 and fifth terminal130-5 may receive the signal from the second base station 110-2 in theMU-MIMO manner.

The first base station 110-1, the second base station 110-2, and thethird base station 110-3 may transmit a signal to the fourth terminal130-4 in the CoMP transmission manner, and the fourth terminal 130-4 mayreceive the signal from the first base station 110-1, the second basestation 110-2, and the third base station 110-3 in the CoMP manner.Also, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1,and 120-2 may exchange signals with the corresponding terminals 130-1,130-2, 130-3, 130-4, 130-5, or 130-6 which belongs to its cell coveragein the CA manner. Each of the base stations 110-1, 110-2, and 110-3 maycontrol D2D communications between the fourth terminal 130-4 and thefifth terminal 130-5, and thus the fourth terminal 130-4 and the fifthterminal 130-5 may perform the D2D communications under control of thesecond base station 110-2 and the third base station 110-3.

Meanwhile, the communication system may support three types of framestructures. A type 1 frame structure may be applied to a frequencydivision duplex (FDD) communication system, a type 2 frame structure maybe applied to a time division duplex (TDD) communication system, and atype 3 frame structure may be applied to an unlicensed band basedcommunication system (e.g., a licensed assisted access (LAA)communication system).

FIG. 3 is a conceptual diagram illustrating a first exemplary embodimentof a type 1 frame.

Referring to FIG. 3 , a radio frame 300 may comprise 10 subframes, and asubframe may comprise 2 slots. Thus, the radio frame 300 may comprise 20slots (e.g., slot #0, slot #1, slot #2, slot #3, . . . , slot #18, andslot #19). The length T_(f) of the radio frame 300 may be 10milliseconds (ms). The length of the subframe may be 1 ms, and thelength T_(slot) of a slot may be 0.5 ms. Here, T_(s) may indicate asampling time, and may be 1/30,720,000s.

The slot may be composed of a plurality of OFDM symbols in the timedomain, and may be composed of a plurality of resource blocks (RBs) inthe frequency domain. The RB may be composed of a plurality ofsubcarriers in the frequency domain. The number of OFDM symbolsconstituting the slot may vary depending on configuration of a cyclicprefix (CP). The CP may be classified into a normal CP and an extendedCP. If the normal CP is used, the slot may be composed of 7 OFDMsymbols, in which case the subframe may be composed of 14 OFDM symbols.If the extended CP is used, the slot may be composed of 6 OFDM symbols,in which case the subframe may be composed of 12 OFDM symbols.

FIG. 4 is a conceptual diagram illustrating a first exemplary embodimentof a type 2 frame.

Referring to FIG. 4 , a radio frame 400 may comprise two half frames,and a half frame may comprise 5 subframes. Thus, the radio frame 400 maycomprise 10 subframes. The length T_(f) of the radio frame 400 may be 10ms. The length of the half frame may be 5 ms. The length of the subframemay be 1 ms. Here, T_(s) may be 1/30,720,000s.

The radio frame 400 may include at least one downlink subframe, at leastone uplink subframe, and a least one special subframe. Each of thedownlink subframe and the uplink subframe may include two slots. Thelength T_(slot) of a slot may be 0.5 ms. Among the subframes included inthe radio frame 400, each of the subframe #1 and the subframe #6 may bea special subframe. For example, when a switching periodicity betweendownlink and uplink is 5 ms, the radio frame 400 may include 2 specialsubframes. Alternatively, the switching periodicity between downlink anduplink is 10 ms, the radio frame 400 may include one special subframe.The special subframe may include a downlink pilot time slot (DwPTS), aguard period (GP), and an uplink pilot time slot (UpPTS).

The downlink pilot time slot may be regarded as a downlink interval andmay be used for cell search, time and frequency synchronizationacquisition of the terminal, channel estimation, and the like. The guardperiod may be used for resolving interference problems of uplink datatransmission caused by delay of downlink data reception. Also, the guardperiod may include a time required for switching from the downlink datareception operation to the uplink data transmission operation. Theuplink pilot time slot may be used for uplink channel estimation, timeand frequency synchronization acquisition, and the like. Transmission ofa physical random access channel (PRACH) or a sounding reference signal(SRS) may be performed in the uplink pilot time slot.

The lengths of the downlink pilot time slot, the guard period, and theuplink pilot time slot included in the special subframe may be variablyadjusted as needed. In addition, the number and position of each of thedownlink subframe, the uplink subframe, and the special subframeincluded in the radio frame 400 may be changed as needed.

In the communication system, a transmission time interval (TTI) may be abasic time unit for transmitting coded data through a physical layer. Ashort TTI may be used to support low latency requirements in thecommunication system. The length of the short TTI may be less than 1 ms.The conventional TTI having a length of 1 ms may be referred to as abase TTI or a regular TTI. That is, the base TTI may be composed of onesubframe. In order to support transmission on a base TTI basis, signalsand channels may be configured on a subframe basis. For example, acell-specific reference signal (CRS), a physical downlink controlchannel (PDCCH), a physical downlink shared channel (PDSCH), a physicaluplink control channel (PUCCH), a physical uplink shared channel(PUSCH), and the like may exist in each subframe.

On the other hand, a synchronization signal (e.g., a primarysynchronization signal (PSS) and a secondary synchronization signal(SSS)) may exist for every 5 subframes, and a physical broadcast channel(PBCH) may exist for every 10 subframes. Also, each radio frame may beidentified by an SFN, and the SFN may be used for defining transmissionof a signal (e.g., a paging signal, a reference signal for channelestimation, a signal for channel state information, etc.) longer thanone radio frame. The periodicity of the SFN may be 1024.

In the LTE system, the PBCH may be a physical layer channel used fortransmission of system information (e.g., master information block(MIB)). The PBCH may be transmitted every 10 subframes. That is, thetransmission periodicity of the PBCH may be 10 ms, and the PBCH may betransmitted once in the radio frame. The same MIB may be transmittedduring 4 consecutive radio frames, and after 4 consecutive radio frames,the MIB may be changed according to a situation of the LTE system. Thetransmission period for which the same MIB is transmitted may bereferred to as a ‘PBCH TTI’, and the PBCH TTI may be 40 ms. That is, theMIB may be changed for each PBCH TTI.

The MIB may be composed of 40 bits. Among the 40 bits constituting theMIB, 3 bits may be used to indicate a system band, 3 bits may be used toindicate physical hybrid automatic repeat request (ARQ) indicatorchannel (PHICH) related information, 8 bits may be used to indicate anSFN, 10 bits may be configured as reserved bits, and 16 bits may be usedfor a cyclic redundancy check (CRC).

The SFN for identifying the radio frame may be composed of a total of 10bits (B9 to B0), and the most significant bits (MSBs) 8 bits (B9 to B2)among the 10 bits may be indicated by the PBCH (i.e., MIB). The MSBs 8bits (B9 to B2) of the SFN indicated by the PBCH (i.e., MIB) may beidentical during 4 consecutive radio frames (i.e., PBCH TTI). The leastsignificant bits (LSBs) 2 bits (B1 to B0) of the SFN may be changedduring 4 consecutive radio frames (i.e., PBCH TTI), and may not beexplicitly indicated by the PBCH (i.e., MIB). The LSBs (2 bits (B1 toB0)) of the SFN may be implicitly indicated by a scrambling sequence ofthe PBCH (hereinafter referred to as ‘PBCH scrambling sequence’).

A Gold sequence generated by being initialized by a cell ID may be usedas the PBCH scrambling sequence, and the PBCH scrambling sequence may beinitialized for each four consecutive radio frames (e.g., each PBCH TTI)based on an operation of ‘mod (SFN, 4)’. The PBCH transmitted in a radioframe corresponding to an SFN with LSBs 2 bits (B1 to B0) set to ‘00’may be scrambled by the Gold sequence generated by being initialized bythe cell ID. Thereafter, the Gold sequences generated according to theoperation of ‘mod (SFN, 4)’ may be used to scramble the PBCH transmittedin the radio frames corresponding to SFNs with LSBs 2 bits (B1 to B0)set to ‘01’, ‘10’, and ‘11’.

Accordingly, the terminal having acquired the cell ID in the initialcell search process may identify the value of the LSBs 2 bits (B1 to B0)of the SFN (e.g., ‘00’, ‘01’, ‘10’, or ‘11’) based on the PBCH scramblesequence obtained in the decoding process for the PBCH (i.e., MIB). Theterminal may use the LSBs 2 bits (B1 to B0) of the SFN obtained based onthe PBCH scrambling sequence and the MSBs 8 bits (B9 to B2) of the SFNindicated by the PBCH (i.e., MIB) so as to identify the SFN (i.e., theentire bits B9 to B0 of the SFN).

On the other hand, the communication system may support not only a hightransmission rate but also technical requirements for various servicescenarios. For example, the communication system may support an enhancedmobile broadband (eMBB) service, an ultra-reliable low-latencycommunication (URLLC) service, a massive machine type communication(mMTC) service, and the like.

The subcarrier spacing of the communication system (e.g., OFDM-basedcommunication system) may be determined based on a carrier frequencyoffset (CFO) and the like. The CFO may be generated by a Doppler effect,a phase drift, or the like, and may increase in proportion to anoperation frequency. Therefore, in order to prevent the performancedegradation of the communication system due to the CFO, the subcarrierspacing may increase in proportion to the operation frequency. On theother hand, as the subcarrier spacing increases, a CP overhead mayincrease. Therefore, the subcarrier spacing may be configured based on achannel characteristic, a radio frequency (RF) characteristic, etc.according to a frequency band.

The communication system may support numerologies defined in Table 1below.

TABLE 1 Numerology (μ) 0 1 2 3 4 5 Subcarrier 15 kHz 30 kHz 60 kHz 120kHz 240 kHz 480 kHz spacing OFDM symbol 66.7 33.3 16.7 8.3 4.2 2.1length [us] CP length [us] 4.76 2.38 1.19 0.60 0.30 0.15 Number of 14 2856 112 224 448 OFDM symbols within 1 ms

For example, the subcarrier spacing of the communication system may beset to 15 kHz, 30 kHz, 60 kHz, or 120 kHz. The subcarrier spacing of theLTE system may be 15 kHz, and the subcarrier spacing of the NR systemmay be 1, 2, 4, or 8 times the conventional subcarrier spacing of 15kHz. If the subcarrier spacing increases by exponentiation units of 2 ofthe conventional subcarrier spacing, the frame structure can be easilydesigned.

The communication system may support a wide frequency band (e.g.,several hundred MHz to tens of GHz). Since the diffractioncharacteristic and the reflection characteristic of the radio wave arepoor in a high frequency band, a propagation loss (e.g., path loss,reflection loss, and the like) in a high frequency band may be largerthan a propagation loss in a low frequency band. Therefore, a cellcoverage of a communication system supporting a high frequency band maybe smaller than a cell coverage of a communication system supporting alow frequency band. In order to solve such the problem, a beamformingscheme based on a plurality of antenna elements may be used to increasethe cell coverage in the communication system supporting a highfrequency band.

The beamforming scheme may include a digital beamforming scheme, ananalog beamforming scheme, a hybrid beamforming scheme, and the like. Inthe communication system using the digital beamforming scheme, abeamforming gain may be obtained using a plurality of RF paths based ona digital precoder or a codebook. In the communication system using theanalog beamforming scheme, a beamforming gain may be obtained usinganalog RF devices (e.g., phase shifter, power amplifier (PA), variablegain amplifier (VGA), and the like) and an antenna array.

Because of the need for expensive digital to analog converters (DACs) oranalog to digital converters (ADCs) for digital beamforming schemes andtransceiver units corresponding to the number of antenna elements, thecomplexity of antenna implementation may be increased to increase thebeamforming gain. In case of the communication system using the analogbeamforming scheme, since a plurality of antenna elements are connectedto one transceiver unit through phase shifters, the complexity of theantenna implementation may not increase greatly even if the beamforminggain is increased. However, the beamforming performance of thecommunication system using the analog beamforming scheme may be lowerthan the beamforming performance of the communication system using thedigital beamforming scheme. Further, in the communication system usingthe analog beamforming scheme, since the phase shifter is adjusted inthe time domain, frequency resources may not be efficiently used.Therefore, a hybrid beam forming scheme, which is a combination of thedigital scheme and the analog scheme, may be used.

When the cell coverage is increased by the use of the beamformingscheme, common control channels and common signals (e.g., referencesignal and synchronization signal) for all terminals belonging to thecell coverage as well as control channels and data channels for eachterminal may also be transmitted based on the beamforming scheme. Inthis case, the common control channels and the common signals for allterminals belonging to the cell coverage may be transmitted based on abeam sweeping scheme.

Also, in the NR system, a synchronization signal/physical broadcastchannel (SS/PBCH) block may also be transmitted in a beam sweepingscheme. The SS/PBCH block may be composed of a PSS, an SSS, a PBCH, andthe like. In the SS/PBCH block, the PSS, the SSS, and the PBCH may beconfigured in a time division multiplexing (TDM) manner. The SS/PBCHblock may be referred also to as an ‘SS block (SSB)’. One SS/PBCH blockmay be transmitted using N consecutive OFDM symbols. Here, N may be aninteger equal to or greater than 4. The base station may periodicallytransmit the SS/PBCH block, and the terminal may acquire frequency/timesynchronization, a cell ID, system information, and the like based onthe SS/PBCH block received from the base station. The SS/PBCH block maybe transmitted as follows.

FIG. 5 is a conceptual diagram illustrating a first exemplary embodimentof a transmission method of SS/PBCH block in a communication system.

As shown in FIG. 5 , one or more SS/PBCH blocks may be transmitted in abeam sweeping scheme within an SS/PBCH block burst set. Up to L SS/PBCHblocks may be transmitted within one SS/PBCH block burst set. L may bean integer equal to or greater than 2, and may be defined in the 3GPPstandard. Depending on a region of a system frequency, L may vary.Within the SS/PBCH block burst set, the SS/PBCH blocks may be locatedconsecutively or distributedly. The consecutive SS/PBCH blocks may bereferred to as an SS/PBCH block burst'. The SS/PBCH block burst set maybe repeated periodically, and system information (e.g., MIB) transmittedthrough the PBCHs of the SS/PBCH blocks within the SS/PBCH block burstset may be the same. An index of the SS/PBCH block, an index of theSS/PBCH block burst, an index of an OFDM symbol, an index of a slot, andthe like may be indicated explicitly or implicitly by the PBCH.

FIG. 6 is a conceptual diagram illustrating a first exemplary embodimentof an SS/PBCH block in a communication system.

As shown in FIG. 6 , signals and a channel are arranged within oneSS/PBCH block in the order of ‘PSS→PBCH→SSS→PBCH’. The PSS, SSS, andPBCH within the SS/PBCH block may be configured in a TDM scheme. In asymbol where the SSS is located, the PBCH may be located in frequencyresources above the SSS and frequency resources below the SSS. That is,the PBCH may be transmitted in both end bands adjacent to the frequencyband in which the SSS is transmitted. When the maximum number L ofSS/PBCH blocks is 8 in the sub 6 GHz frequency band, an SS/PBCH blockindex may be identified based on a demodulation reference signal usedfor demodulating the PBCH (hereinafter, referred to as ‘PBCH DMRS’).When the maximum number L of SSBs is 64 in the over 6 GHz frequencyband, LSB 3 bits of 6 bits representing the SS/PBCH block index may beidentified based on the PBCH DMRS, and the remaining MSB 3 bits may beidentified based on a payload of the PBCH.

The maximum system bandwidth that can be supported in the NR system maybe 400 MHz. The size of the maximum bandwidth that can be supported bythe terminal may vary depending on the capability of the terminal.Therefore, the terminal may perform an initial access procedure (e.g.,initial connection procedure) by using some of the system bandwidth ofthe NR system supporting a wide band. In order to support accessprocedures of terminals supporting various sizes of bandwidths, SS/PBCHblocks may be multiplexed in the frequency domain within the systembandwidth of the NR system supporting a wide band. In this case, theSS/PBCH blocks may be transmitted as follows.

FIG. 7 is a conceptual diagram illustrating a second exemplaryembodiment of a method of transmitting SS/PBCH blocks in a communicationsystem.

As shown in FIG. 7 , a wideband component carrier (CC) may include aplurality of bandwidth parts (BWPs). For example, the wideband CC mayinclude 4 BWPs. The base station may transmit SS/PBCH blocks in therespective BWPs #0 to #3 belonging to the wideband CC. The terminal mayreceive the SS/PBCH block(s) from one or more BWPs of the BWPs #0 to #3,and may perform an initial access procedure using the received SS/PBCHblock.

After detecting the SS/PBCH block, the terminal may acquire systeminformation (e.g., remaining minimum system information (RMSI)), and mayperform a cell access procedure based on the system information. TheRMSI may be transmitted on a PDSCH scheduled by a PDCCH. Configurationinformation of a control resource set (CORESET) in which the PDCCHincluding scheduling information of the PDSCH through which the RMSI istransmitted may be transmitted on a PBCH within the SS/PBCH block. Aplurality of SS/PBCH blocks may be transmitted in the entire systemband, and one or more SS/PBCH blocks among the plurality of SS/PBCHblocks may be SS/PBCH block(s) associated with the RMSI. The remainingSS/PBCH blocks may not be associated with the RMSI. The SS/PBCH blockassociated with the RMSI may be defined as a ‘cell defining SS/PBCHblock’. The terminal may perform a cell search procedure and an initialaccess procedure by using the cell-defining SS/PBCH block. The SS/PBCHblock not associated with the RMSI may be used for a synchronizationprocedure and/or a measurement procedure in the corresponding BWP. TheBWP(s) through which the SS/PBCH block is transmitted may be limited toone or more BWPs within a wide bandwidth.

The RMSI may be obtained by performing an operation to obtainconfiguration information of a CORESET from the SS/PBCH block (e.g.,PBCH), an operation of detecting a PDCCH based on the configurationinformation of the CORESET, an operation to obtain schedulinginformation of a PDSCH from the PDCCH, and an operation to receive theRMSI through the PDSCH. A transmission resource of the PDCCH may beconfigured by the configuration information of the CORESET. A mappingpatter of the RMSI CORESET pattern may be defined as follows. The RMSICORESET may be a CORESET used for transmission and reception of theRMSI.

FIG. 8A is a conceptual diagram illustrating an RMSI CORESET mappingpattern #1 in a communication system, FIG. 8B is a conceptual diagramillustrating an RMSI CORESET mapping pattern #2 in a communicationsystem, and FIG. 8C is a conceptual diagram illustrating an RMSI CORESETmapping pattern #3 in a communication system.

As shown in FIGS. 8A to 8C, one RMSI CORESET mapping pattern among theRMSI CORESET mapping patterns #1 to #3 may be used, and a detailedconfiguration according to the one RMSI CORESET mapping pattern may bedetermined. In the RMSI CORESET mapping pattern #1, the SS/PBCH block,the CORESET (i.e., RMSI CORESET), and the PDSCH (i.e., RMSI PDSCH) maybe configured in a TDM scheme. The RMSI PDSCH may mean the PDSCH throughwhich the RMSI is transmitted. In the RMSI CORESET mapping pattern #2,the CORESET (i.e., RMSI CORESET) and the PDSCH (i.e., RMSI PDSCH) may beconfigured in a TDM scheme, and the PDSCH (i.e., RMSI PDSCH) and theSS/PBCH block may be configured in a frequency division multiplexing(FDM) scheme. In the RMSI CORESET mapping pattern #3, the CORESET (i.e.,RMSI CORESET) and the PDSCH (i.e., RMSI PDSCH) may be configured in aTDM scheme, and the CORESET (i.e., RMSI CORESET) and the PDSCH (i.e.,RMSI PDSCH) may be multiplexed with the SS/PBCH block in a FDM scheme.

In the frequency band of 6 GHz or below, only the RMSI CORESET mappingpattern #1 may be used. In the frequency band of 6 GHz or above, all ofthe RMSI CORESET mapping patterns #1, #2, and #3 may be used. Thenumerology of the SS/PBCH block may be different from that of the RMSICORESET and the RMSI PDSCH. Here, the numerology may be a subcarrierspacing. In the RMSI CORESET mapping pattern #1, a combination of allnumerologies may be used. In the RMSI CORESET mapping pattern #2, acombination of numerologies (120 kHz, 60 kHz) or (240 kHz, 120 kHz) maybe used for the SS/PBCH block and the RMSI CORESET/PDSCH. In the RMSICORESET mapping pattern #3, a combination of numerologies (120 kHz, 120kHz) may be used for the SS/PBCH block and the RMSI CORESET/PDSCH.

One RMSI CORESET mapping pattern may be selected from the RMSI CORESETmapping patterns #1 to #3 according to the combination of the numerologyof the SS/PBCH block and the numerology of the RMSI CORESET/PDSCH. Theconfiguration information of the RMSI CORESET may include Table A andTable B. Table A may represent the number of resource blocks (RBs) ofthe RMSI CORESET, the number of symbols of the RMSI CORESET, and anoffset between an RB (e.g., starting RB or ending RB) of the SS/PBCHblock and an RB (e.g., starting RB or ending RB) of the RMSI CORESET.Table B may represent the number of search space sets per slot, anoffset of the RMSI CORESET, and an OFDM symbol index in each of the RMSICORESET mapping patterns. Table B may represent information forconfiguring a monitoring occasion of the RMSI PDCCH. Each of Table A andTable B may be composed of a plurality of sub-tables. For example, TableA may include sub-tables 13-1 to 13-8 defined in the technicalspecification (TS) 38.213, and Table B may include sub-tables 13-9 to13-13 defined in the TS 38.213. The size of each of Table A and Table Bmay be 4 bits.

In the NR system, a PDSCH may be mapped to the time domain according toa PDSCH mapping type A or a PDSCH mapping type B. The PDSCH mappingtypes A and B may be defined as Table 2 below.

TABLE 2 PDSCH mapping Normal CP Extended CP type S L S + L S L S + LType A {0, 1, 2, 3} {3, . . . , 14} {3, . . . , 14} {0, 1, 2, 3} {3, . .. , 12} {3, . . . , 12} (Note 1) (Note 1) Type B {0, . . . , 12} {2, 4,7} {2, . . . , 14} {0, . . . , 10} {2, 4, 6} {2, . . . , 12} (Note 1): S= 3 is applicable only if dmrs-TypeA-Position = 3

The type A (i.e., PDSCH mapping type A) may be slot-based transmission.When the type A is used, a position of a start symbol of a PDSCH may beset to one of {0, 1, 2, 3}. When the type A and a normal CP are used,the number of symbols constituting the PDSCH (e.g., the duration of thePDSCH) may be set to one of 3 to 14 within a range not exceeding a slotboundary. The type B (i.e., PDSCH mapping type B) may be non-slot-basedtransmission. When the type B is used, a position of a start symbol of aPDSCH may be set to one of 0 to 12. When the type B and the normal CPare used, the number of symbols constituting the PDSCH (e.g., theduration of the PDSCH) may be set to one of {2, 4, 7} within a range notexceeding a slot boundary. A DMRS (hereinafter, referred to as ‘PDSCHDMRS’) for demodulation of the PDSCH (e.g., data) may be determined by avalue of ID indicating the PDSCH mapping type (e.g., type A or type B)and the length. The ID may be defined differently according to the PDSCHmapping type.

Meanwhile, NR-unlicensed (NR-U) is being discussed in the NRstandardization meeting. The NR-U system may increase network capacityby improving the utilization of limited frequency resources. The NR-Usystem may support operation in an unlicensed band (e.g., unlicensedspectrum).

In the NR-U system, the terminal may determine whether a signal istransmitted from a base station based on a discovery reference signal(DRS) received from the corresponding base station in the same manner asin the general NR system. In the NR-U system in a Stand-Alone (SA) mode,the terminal may acquire synchronization and/or system information basedon the DRS. In the NR-U system, the DRS may be transmitted according toa regulation of the unlicensed band (e.g., transmission band,transmission power, transmission time, etc.). For example, according toOccupied Channel Bandwidth (OCB) regulations, signals may be configuredand/or transmitted to occupy 80% of the total channel bandwidth (e.g.,20 MHz).

In the NR-U system, a communication node (e.g., base station, terminal)may perform a Listen Before Talk (LBT) procedure before transmitting asignal and/or a channel for coexistence with another system. The signalmay be a synchronization signal, a reference signal (e.g., DRS, DMRS,channel state information (CSI)-RS, phase tracking (PT)-RS, soundingreference signal (SRS)), or the like. The channel may be a downlinkchannel, an uplink channel, a sidelink channel, or the like. Inexemplary embodiments, a signal may mean the ‘signal’, the ‘channel’, orthe ‘signal and channel’. The LBT procedure may be an operation forchecking whether a signal is transmitted by another communication node.If it is determined by the LBT procedure that there is no transmissionsignal (e.g., when the LBT procedure is successful), the communicationnode may transmit a signal in the unlicensed band. If it is determinedby the LBT procedure that a transmission signal exists (e.g., when theLBT fails), the communication node may not be able to transmit a signalin the unlicensed band. The communication node may perform a LBTprocedure according to one of various categories before transmission ofa signal. The category of LBT may vary depending on the type of thetransmission signal.

Meanwhile, NR vehicle-to-everything (V2X) communication technology isbeing discussed in the NR standardization meeting. The NR V2Xcommunication technology may be a technology that supports communicationbetween vehicles, communication between a vehicle and an infrastructure,communication between a vehicle and a pedestrian, and the like based ondevice-to-device (D2D) communication technologies.

The NR V2X communication (e.g., sidelink communication) may be performedaccording to three transmission schemes (e.g., unicast scheme, broadcastscheme, groupcast scheme). When the unicast scheme is used, the firstterminal may transmit data (e.g., sidelink data) to the second terminal.When the broadcast scheme is used, the first terminal may transmit datato all terminals. When the groupcast scheme is used, the first terminalmay transmit data to a group (e.g., groupcast group) composed of aplurality of terminals.

When the unicast scheme is used, the second terminal may transmitfeedback information (e.g., acknowledgment (ACK) or negative ACK (NACK))to the first terminal in response to data received from the firstterminal. In the exemplary embodiments below, the feedback informationmay be referred to as a ‘feedback signal’, a ‘physical sidelink feedbackchannel (PSFCH) signal’, or the like. When ACK is received from thesecond terminal, the first terminal may determine that the data has beensuccessfully received at the second terminal. When NACK is received fromthe second terminal, the first terminal may determine that the secondterminal has failed to receive the data. In this case, the firstterminal may transmit additional information to the second terminalbased on an HARQ scheme. Alternatively, the first terminal may improve areception probability of the data at the second terminal byretransmitting the same data to the second terminal.

When the broadcast scheme is used, a procedure for transmitting feedbackinformation for data may not be performed. For example, systeminformation may be transmitted in the broadcast scheme, and the terminalmay not transmit feedback information for the system information to thebase station. Therefore, the base station may not identify whether thesystem information has been successfully received at the terminal. Tosolve this problem, the base station may periodically broadcast thesystem information.

When the groupcast scheme is used, a procedure for transmitting feedbackinformation for data may not be performed. For example, necessaryinformation may be periodically transmitted in the groupcast scheme,without the procedure for transmitting feedback information. However,when the candidates of terminals participating in the groupcastscheme-based communication and/or the number of the terminalsparticipating in that is limited, and the data transmitted in thegroupcast scheme is data that should be received within a preconfiguredtime (e.g., data sensitive to delay), it may be necessary to transmitfeedback information also in the groupcast sidelink communication. Thegroupcast sidelink communication may mean sidelink communicationperformed in the groupcast scheme. When the feedback informationtransmission procedure is performed in the groupcast sidelinkcommunication, data can be transmitted and received efficiently andreliably.

In addition, data reliability at the receiving terminal may be improvedby appropriately adjusting a transmit power of the transmitting terminalaccording to a transmission environment. Interference to other terminalsmay be mitigated by appropriately adjusting the transmit power of thetransmitting terminal. Energy efficiency can be improved by reducingunnecessary transmit power. A power control scheme may be classifiedinto an open-loop power control scheme and a closed-loop power controlscheme. In the open-loop power control scheme, the transmitting terminalmay determine the transmit power in consideration of configuration, ameasured environment, etc. In the closed-loop power control scheme, thetransmitting terminal may determine the transmit power based on atransmit power control (TPC) command received from the receivingterminal.

It may be difficult due to various causes including a multipath fadingchannel, interference, and the like to predict a received signalstrength at the receiving terminal. Accordingly, the receiving terminalmay adjust a receive power level (e.g., receive power range) byperforming an automatic gain control (AGC) operation to prevent aquantization error of the received signal and maintain a proper receivepower. In the communication system, the terminal may perform the AGCoperation using a reference signal received from the base station.However, in the sidelink communication (e.g., V2X communication), thereference signal may not be transmitted from the base station. That is,in the sidelink communication, communication between terminals may beperformed without the base station. Therefore, it may be difficult toperform the AGC operation in the sidelink communication. In the sidelinkcommunication, the transmitting terminal may first transmit a signal(e.g., reference signal) to the receiving terminal before transmittingdata, and the receiving terminal may adjust a receive power range (e.g.,receive power level) by performing an AGC operation based on the signalreceived from the transmitting terminal. Thereafter, the transmittingterminal may transmit sidelink data to the receiving terminal. Thesignal used for the AGC operation may be a signal duplicated from asignal to be transmitted later or a signal preconfigured between theterminals.

A time period required for the ACG operation may be 15 μs. When asubcarrier spacing of 15 kHz is used in the NR system, a time period(e.g., length) of one symbol (e.g., OFDM symbol) may be 66.7 μs. When asubcarrier spacing of 30 kHz is used in the NR system, a time period ofone symbol (e.g., OFDM symbol) may be 33.3 μs. In the followingexemplary embodiments, a symbol may mean an OFDM symbol. That is, a timeperiod of one symbol may be twice or more than a time period requiredfor the ACG operation.

For sidelink communication, it may be necessary to transmit a datachannel for data transmission and a control channel including schedulinginformation for data resource allocation. In sidelink communication, thedata channel may be a physical sidelink shared channel (PSSCH), and thecontrol channel may be a physical sidelink control channel (PSCCH). Thedata channel and the control channel may be multiplexed in a resourcedomain (e.g., time and frequency resource domains).

FIG. 9 is a conceptual diagram illustrating exemplary embodiments of amethod for multiplexing a control channel and a data channel in sidelinkcommunication.

Referring to FIG. 9 , sidelink communication may support an option 1A,an option 1B, an option 2, and an option 3. When the option 1A and/orthe option 1B is supported, a control channel and a data channel may bemultiplexed in the time domain. When the option 2 is supported, acontrol channel and a data channel may be multiplexed in the frequencydomain. When the option 3 is supported, a control channel and a datachannel may be multiplexed in the time and frequency domains. Thesidelink communication may basically support the option 3.

In the sidelink communication (e.g., NR-V2X sidelink communication), abasic unit of resource configuration may be a subchannel. The subchannelmay be defined with time and frequency resources. For example, thesubchannel may be composed of a plurality of symbols (e.g., OFDMsymbols) in the time domain, and may be composed of a plurality ofresource blocks (RBs) in the frequency domain. The subchannel may bereferred to as an RB set. In the subchannel, a data channel and acontrol channel may be multiplexed based on the option 3.

In the sidelink communication (e.g., NR-V2X sidelink communication),transmission resources may be allocated based on a mode 1 or a mode 2.When the mode 1 is used, a base station may allocate sidelinkresource(s) for data transmission within a resource pool to atransmitting terminal, and the transmitting terminal may transmit datato a receiving terminal using the sidelink resource(s) allocated by thebase station. Here, the transmitting terminal may be a terminal thattransmits data in sidelink communication, and the receiving terminal maybe a terminal that receives the data in sidelink communication.

When the mode 2 is used, a transmitting terminal may autonomously selectsidelink resource(s) to be used for data transmission by performing aresource sensing operation and/or a resource selection operation withina resource pool. The base station may configure the resource pool forthe mode 1 and the resource pool for the mode 2 to the terminal(s). Theresource pool for the mode 1 may be configured independently from theresource pool for the mode 2. Alternatively, a common resource pool maybe configured for the mode 1 and the mode 2.

Hereinafter, sidelink communication methods based on one or morebandwidth parts (BWPs) in a communication system will be described. Evenwhen a method (e.g., transmission or reception of a signal) to beperformed at a first communication node among communication nodes isdescribed, a corresponding second communication node may perform amethod (e.g., reception or transmission of the signal) corresponding tothe method performed at the first communication node. That is, when anoperation of a transmitting terminal is described, a correspondingreceiving terminal may perform an operation corresponding to theoperation of the transmitting terminal. Conversely, when an operation ofa receiving terminal is described, a corresponding transmitting terminalmay perform an operation corresponding to the operation of the receivingterminal.

BWP has been introduced to support terminal capability, increaseterminal energy efficiency, and support various numerologies. In acommunication system supporting FDD, each of up to 4 downlink BWPs andup to 4 uplink BWPs may be configured for each serving cell in theterminal. In a communication system supporting TDD, a BWP pairconsisting of a downlink BWP and an uplink BWP may be configured in theterminal. Up to 4 BWP pairs may be configured in the terminal. When asupplementary uplink carrier is configured, four additional uplink BWPsmay be configured in the supplementary uplink carrier of the terminal.Even when a plurality of BWPs are configured in the terminal, theterminal may activate one BWP at a preconfigured time (e.g., at a giventime). A switching operation between a plurality of BWPs may beindicated by system information, RRC signaling, a timer, a MAC controlelement (CE), and/or L1 control information.

BWP may be used for sidelink communication. A BWP configured forsidelink communication may be referred to as ‘SL BWP’. A UL BWP may beused as an SL BWP. One SL BWP having one numerology may be configuredwithin a sidelink carrier. The terminal may assume that the numerologyof the SL BWP is the same as that of an active UL BWP. When thenumerology of the active UL BWP is different from that of the SL BWP,the terminal may assume that the SL BWP is deactivated. In addition,unlike a DL BWP and/or UL BWP, a separate signaling operation foractivation and/or deactivation of the SL BWP may not be supported. Insidelink communication, terminals having various movement speeds maycoexist, and support of various numerologies suitable for terminalshaving various movement speeds may be required. Since one BWP supportingone numerology can be supported in the existing sidelink communication,operations of configuring and/or supporting multiple SL BWPs may berequired to support various numerologies as in downlink and/or uplink.Accordingly, operations of configuring and/or supporting a plurality ofSL BWPs for supporting various numerologies in sidelink communicationmay be introduced. In addition, operations of configuring and/orsupporting a plurality of SL BWPs may be introduced for reasons ofsupporting various terminal capabilities and/or increasing energyefficiency in sidelink. In exemplary embodiments below, methods forsupporting configuration and/or operations of a plurality of SL BWPs insidelink communication will be proposed. The SL BWP may refer to a BWPused for sidelink communication. When an SL BWP is not configuredindependently from a UL BWP (or DL BWP), and a UL BWP (or DL BWP) isused as an SL BWP, the SL BWP may be interpreted as the UL BWP (or DLBWP) in the exemplary embodiments below.

In order to support operations of configuring and/or supporting aplurality of SL BWPs, a signaling operation for activation/deactivationof one or more SL BWPs and/or a signaling operation for switchingbetween SL BWPs may be required. Accordingly, in the below exemplaryembodiments, methods for activation/deactivation of an SL BWP and amethod for SL BWP switching will be proposed.

When a separate signaling operation for SL BWP activation/deactivationis not supported, in order to support switching between a plurality ofSL BWPs to which a plurality of numerologies (e.g., differentnumerologies) are applied, and activation and/or deactivation thereof, aplurality of UL BWPs to which a plurality of numerologies (e.g.,different numerologies) are applied may be configured, and a mappingrelationship between UL BWP and SL BWP may be configured. Based on themapping relationship between UL BWP and SL BWP, switching, activation,and/or deactivation for an SL BWP may be supported according toswitching, activation, and/or deactivation for a UL BWP.

For example, a UL BWP#0 having a subcarrier spacing (SCS) of 15 kHz anda UL BWP#1 having an SCS of 30 kHz may be configured, and an SL BWP#0having an SCS of 15 kHz and an SL BWP#1 having an SCS of 30 kHz may beconfigured. The UL BWP#0 may be mapped to the SL BWP#0, and the UL BWP#1may be mapped to the SL BWP#1. That is, the mapping relationship betweenthe SL BWPs and the UL BWPs may be one-to-one mapping relationship. Theswitching, activation and/or deactivation operation of the SL BWP#0 maybe performed according to the switching, activation and/or deactivationoperation of the UL BWP#0, and the switching, activation and/ordeactivation operation of the SL BWP#1 may be performed according to theswitching, activation, and/or deactivation operation of the UL BWP#1.

For example, when a UL BWP (e.g., operating UL BWP) is switched from theUL BWP#0 to the UL BWP#1, an SL BWP (e.g., operating SL BWP) may beswitched from the SL BWP#0 to the SL BWP#1 according to the mappingrelationship between the UL BWPs and the SL BWPs. In the switched SLBWP#1, sidelink communication between terminals may be performed. Inaddition, when a UL BWP activation/deactivation operation is performed,an SL BWP activation/deactivation operation may be performed accordingto the mapping relationship between the UL BWPs and the SL BWPs. Thesidelink communication between terminals may be performed in theactivated SL BWP. That is, when a switching, activation, and/ordeactivation operation of a UL BWP is performed, a switching,activation, and/or deactivation operation of a corresponding SL BWP maybe automatically performed without separate signaling according to themapping relationship between the UL BWPs and the SL BWPs. A switchingoperation of an SL BWP may be triggered by performing a switchingoperation of a corresponding UL BWP, an activation operation of an SLBWP may be triggered by performing an activation operation of acorresponding UL BWP, and a deactivation operation of an SL BWP may betriggered by performing a deactivation operation of a corresponding ULBWP.

The mapping relationship between UL BWP and SL BWP may be one-to-onemapping relationship, n-to-one mapping relationship, or one-to-n mappingrelationship. Here, n may be a natural number. The same numerology maybe configured to a UL BWP and an SL BWP having the mapping relationship.The mapping relationship (e.g., configuration information of the mappingrelationship) between UL BWP and SL BWP may be transmitted using one ora combination of two or more among system information (e.g.,cell-specific information), RRC signaling (e.g., UE-specific RRCsignaling), a MAC CE, and L1 control information (e.g., downlink controlinformation (DCI) and/or sidelink control information (SCI)).Alternatively, the mapping relationship may be configured implicitlybetween a UL BWP and an SL BWP to which the same numerology isconfigured. A mapping relationship between a UL BWP and an SL BWP may beconfigured by configuring the same ID to the UL BWP and the SL BWP. Forexample, it may be considered that a mapping relationship is configuredbetween a UL BWP and an SL BWP having the same numerology (e.g., SCS)and the same ID.

Alternatively, a switching, activation, and/or deactivation operation ofan SL BWP may be performed through separate signaling as in a DL BWP (orUL BWP). The separate signaling may be one or a combination of two ormore among system information signaling, cell-specific RRC signaling,terminal-specific RRC signaling, signaling for timer setting, MAC CEsignaling, and L1 control information (e.g., DCI or SCI) signaling. Whenthe L1 control information signaling is used, a BWP indicator indicatingexecution of an SL BWP switching operation (or, SL BWP activationoperation or SL BWP deactivation operation) may be added in DCI (e.g.,DCI format 3_0) and/or SCI (e.g., 1st stage SCI and/or 2nd stage SCI)for sidelink scheduling. The first stage SCI may have an SCI format 1-A,and the second stage SCI may have an SCI format 2-A or SCI format 2-B.

Each of DCI and SCI may include a first BWP indicator indicating toperform an SL BWP switching operation, a second BWP indicator indicatingto perform an SL BWP activation operation, and/or a third BWP indicatorindicating to perform an SL BWP deactivation operation. Information(e.g., offset) indicating an execution time of the SL switchingoperation (or, SL BWP activation operation or SL BWP deactivationoperation) may be configured by system information, an RRC signalingmessage, and/or a MAC CE. The offset configured by system information,RRC signaling message, and/or MAC CE may be an offset between a slot inwhich the DCI or SCI indicating to perform the SL switching operation(or, SL BWP activation operation or SL BWP deactivation operation) isreceived and a slot in which the SL BWP switching operation (or, SLactivation operation or SL BWP deactivation operation) is performed.When the DCI and/or SCI indicates to perform the SL switching operation(or, SL BWP activation operation or SL BWP deactivation operation), theSL switching operation (or, SL BWP activation operation or SL BWPdeactivation operation) may be performed at the time indicated by thesystem information, RRC signaling message, and/or MAC CE. That is, theSL switching operation (or, SL BWP activation operation or SL BWPdeactivation operation) may be performed in a slot after a preconfiguredoffset from the slot in which the DCI or SCI is received.

When sidelink communication is performed based on the mode 1, the basestation may indicate the terminal to perform the SL BWP switchingoperation by using the BWP indicator included in the DCI. A transmittingterminal may receive the DCI from the base station, and may identify theBWP indicator included in the DCI. In this case, the transmittingterminal may inform a receiving terminal of the SL BWP switchingoperation indicated by the base station by transmitting SCI (e.g., firststage SCI and/or second stage SCI) including a BWP indicator (e.g., theBWP indicator included in the DCI). The receiving terminal may receivethe SCI from the transmitting terminal, and may determine that the SLBWP switching operation is indicated by the base station by identifyingthe BWP indicator included in the SCI. The transmitting terminal and/orthe receiving terminal may perform the SL BWP switching operation basedon the BWP indicator, and sidelink communication between thetransmitting terminal and the receiving terminal may be performed in aswitched SL BWP. In exemplary embodiments, the transmitting terminal maybe a terminal that transmits sidelink data, and the receiving terminalmay be a terminal that receives the sidelink data.

When sidelink communication is performed based on the mode 2, atransmitting terminal may autonomously determine whether to perform anSL BWP switching operation. When it is determined to perform the SL BWPswitching operation, the transmitting terminal may transmit SCI (e.g.,first stage SCI and/or second stage SCI) including a BWP indicator to areceiving terminal. The receiving terminal may receive the SCI from thetransmitting terminal, and may determine that execution of the SL BWPswitching operation is indicated by identifying the BWP indicatorincluded in the SCI. The transmitting terminal and/or the receivingterminal may perform the SL BWP switching operation based on the BWPindicator, and sidelink communication between the transmitting terminaland the receiving terminal may be performed in a switched SL BWP.

In the existing sidelink communication, a PSCCH on which a first stageSCI is transmitted and a PSSCH (e.g., a PSSCH on which sidelink datascheduled by the first stage SCI is transmitted or a PSSCH on which asecond stage SCI associated with the first stage SCI is transmitted) maybe mapped to the same slot. A frequency resource assignment for a firstsubchannel may be configured to be the same as a subchannel in which theSCI is detected, and a time resource assignment for a first slot may beconfigured to be the same as a slot in which the SCI detected. When oneor more SL BWPs are configured and an SL BWP switching operation by SCIis supported, a PSCCH on which a first-stage SCI is transmitted and aPSSCH on which a second-stage SCI and/or data is transmitted may not beconfigured in the same slot and the same first subchannel (e.g.,subchannel having the same index). Accordingly, the first stage SCI mayadditionally include a slot offset and/or a subchannel offset. The slotoffset included in the first stage SCI may be an offset between a slot(e.g., a slot in an existing SL BWP (i.e., SL BWP before switching)) inwhich a PSCCH on which the corresponding first stage SCI is transmittedis configured and a slot (e.g., a slot in a switched SL BWP) in which aPSSCH associated with the PSCCH (e.g., first stage SCI) is configured.The subchannel offset included in the first stage SCI may be an offsetbetween a subchannel (e.g., a subchannel in the existing SL BWP) inwhich the PSCCH on which the corresponding first stage SCI istransmitted is configured and a first subchannel (e.g., a subchannel inthe switched SL BWP) in which the PSSCH associated with the PSCCH (e.g.,first stage SCI) is configured. In exemplary embodiments below, asignaling method(s) of the slot offset and/or subchannel offset will bedescribed.

The slot offset may be preconfigured in consideration of a numerology.An index of the subchannel on which the first stage SCI is transmittedmay be configured to be maintained in the switched SL BWP. Thisoperation may be indicated by the subchannel offset. In this case, aseparate signaling operation for the subchannel offset may not berequired. The BWP indicator, slot offset, and/or subchannel offset maybe configured using reserved bits included in the SCI. When the BWPindicator, slot offset, and/or subchannel offset are added in the SCI(e.g., first-stage SCI and/or second-stage SCI) in a situation ofcoexistence with legacy sidelink terminals, the legacy sidelinkterminals cannot detect the BWP indicator, slot offset, and/orsubchannel offset included in the SCI, and terminals capable ofrecognizing the additional information may perform sidelinkcommunication by using the additional information (e.g., BWP indicator,slot offset, and/or subchannel offset) included in the SCI.

An additional indicator (e.g., an indicator having a size of 1 bit) maybe required to inform whether or not the terminals capable ofrecognizing the additional information use the additional information.For example, the indicator set to a first value (e.g., 0) may indicatethat the terminals do not need to use the additional information(s), andthe indicator set to a second value (e.g., 1) may indicate that theterminals need to use the additional information(s). When the indicatoris set to the second value, the terminal may perform an SL BWP switchingoperation using the additional information (e.g., BWP indicator, slotoffset, and/or subchannel offset) included in the SCI.

Alternatively, without the above-described indicator, when a BWP (e.g.,SL BWP) indicated by the BWP indicator is different from a current BWP,the terminal may perform an SL BWP switching operation by usingadditional information (e.g., slot offset and/or subchannel offset).Even when at least one of the BWP indicator, slot offset, and subchanneloffset is introduced, the above-described operations may be performed.When numerologies of the SL BWPs are different, a reference unit of eachof the slot offset and the subchannel offset may be a numerology of theexisting SL BWP or the switched SL BWP. The numerology used as thereference unit may be preconfigured. A smallest numerology or a largestnumerology among the numerology of the existing SL BWP and thenumerology of the switched SL BWP may be configured to be used as thereference unit.

In order to signal the slot offset and/or subchannel offset in theswitched BWP, an existing scheduling method may be used. In the existingsidelink communication, up to N resources (e.g., up to N schedulingresources) may be reserved in advance through SCI. The maximum Nresources may include a scheduling resource at a time of receiving thecorresponding SCI. Here, N may be a natural number. Based on this, thescheduling resource at the time of receiving of the SCI may be ignored,and resources used for actual data transmission/reception operation inthe switched BWP may be from a second scheduling resource according tothe corresponding SCI. Slot location information indicating the secondscheduling resource in scheduling information included in the SCI may beused as a slot offset from the time of receiving the corresponding SCI.Subchannel location information indicating the second schedulingresource in the scheduling information included in the SCI may be usedas an index of a subchannel in the switched BWP.

In the case that the scheduling resource at the time of receiving theSCI is ignored, up to N-1 resources may be reserved. Alternatively, thescheduling resource at the time of receiving the SCI may be used fordata transmission/reception operation in the existing SL BWP (e.g., SLBWP before switching), and a resource used for datatransmission/reception operation in the switched SL BWP may be from thesecond scheduling resource according to the SCI. In this case, like theexisting sidelink communication, a maximum of N resources may bereserved by the SCI. Alternatively, the scheduling resource at the timeof receiving the SCI may be used only for data transmission/receptionoperation in the switched SL BWP. In this case, a time at which thescheduling resource is applied may be signaled separately at the time ofreceiving the SCI. Alternatively, the time at which the schedulingresource is applied may be a time at which a preconfigured slot offsetis applied. If SL BWP configurations including the numerologies of theSL BWPs are different, a preconfigured one numerology (or, a smallestnumerology or a largest numerology) of the numerology of the existing SLBWP and the numerology of the switched SL BWP may be applied to variousinformation (e.g., size and number of sub channels, slot offset,subchannel offset, and reference unit) between reserved resources in thereserved resource information. In this case, when the number ofsubchannels between the BWP before switching and the switched BWP isdifferent, a signaling operation may be performed based on the number ofbits of an information size in consideration of the number ofsubchannels of the BWP before switching. After that, the correspondinginformation may be truncated from the MSB to fit the information size inconsideration of the number of subchannels of the switched BWP.Alternatively, the information may be interpreted by applying padding(e.g., 0) to the MSB to fit the information size in consideration of thenumber of subchannels of the switched BWP. The terminal may receivescheduling information for reserving N resources. In this case, when aBWP indicator is present in the SCI and a BWP indicated by the BWPindicator is different from a current BWP, the terminal may perform theaforementioned SL BWP switching operation.

When a current carrier is not an independent SL carrier (e.g.,independent sidelink carrier), some of uplink (UL) resources may beconfigured as sidelink (SL) resources. A bitmap having a specific lengthmay be repeatedly applied to the remaining slots excluding slot(s) inwhich at least X or more UL symbols are not configured and slot(s) inwhich sidelink SSB (S-SSB) is transmitted among slots within a specificperiod. Here, X may be a natural number. The bitmap may include one ormore bits, and a slot mapped to a bit set to 1 may be used as an SLresource. For example, within a period of 10240 slots composed of slotsto which an SCS of 15 kHz is applied, the S-SSB may be transmittedaccording to a periodicity of 160 ms, and two slots used fortransmission of the S-SSB may exist within a period of the S-SSB. Inthis case, the number of slots used for transmission of the S-SSB may be128 within a period of 10240 slots.

When the length of the bitmap is 10, the SL resources may be configuredby continuously applying the bitmap having the size of 10 bits within aperiod of 10240 slots. Here, it may be assumed that X or more UL symbolsare configured in each of 10240 slots. In order to divide the number ofavailable slots within a period of 1024 slots by the length (e.g., size)of the bitmap without a remainder, two spare slots may be required.Within a period of 10240 slots, the bitmap may be applied 1011 (i.e.,(10240-128-2)/10) times. When the bitmap is set to ‘1111000000’, a slotmapped to a bit set to 1 may be used as an SL resource. Therefore, 4044slots may be configured as SL resources. 4044 slots of the 10240 slotsmay be used for sidelink communication through SL resource poolconfiguration.

When a DL/UL BWP switching operation is performed, a delay time mayoccur. When a DL BWP switching operation is performed, the terminal mayperform a DL reception operation in a switched DL BWP after a delay time(hereinafter, referred to as ‘T₁’). When a UL BWP switching operation isperformed, the terminal may perform a UL transmission operation in aswitched UL BWP after T₁. When some of UL resources are configured as SLresources, the terminal should be able to perform UL transmission in aslot after T₁ from a triggering time of the UL BWP switching operation.The SL resources may be configured in consideration of theabove-described operation. Accordingly, in exemplary embodiments below,methods of configuring SL resources according to a UL BWP switchingoperation in various cases including a case in which a mappingrelationship between UL BWP and SL BWP is configured will be described.When a UL BWP switching operation is performed, the terminal should beable to perform UL transmission in a switched BWP after T₁ for the ULBWP switching operation. The following various cases may be consideredaccording to the configuration of the mapping relationship between ULBWP and SL BWP and/or the numerology in each BWP.

Case 1: UL BWP switching occurs→SL BWP switching occurs→Configuration ofSL resources within UL resources is necessary

Case 2: UL BWP switching occurs→SL BWP switching occurs→Configuration ofSL resources within UL resources is unnecessary when UL resources and SLresources are configured independently

Case 3: Only UL BWP switching occurs (e.g., SL BWP switching does notoccur)→ a numerology of a new UL BWP (e.g., switched UL BWP) is the sameas a numerology of an existing SL BWP (e.g., SL BWP beforeswitching)→Configuration of SL resources within UL resources isunnecessary when UL resources and SL resources are configuredindependently

Case 4: Only UL BWP switching occurs (e.g., SL BWP switching does notoccur)→ a numerology of a new UL BWP (e.g., switched UL BWP) isdifferent from a numerology of an existing SL BWP (e.g., SL BWP beforeswitching)→SL BWP deactivation

In Case 1 and Case 2, a mapping relationship between UL BWP and SL BWPmay be configured, and an SL BWP switching operation may beautomatically performed as a corresponding UL BWP switching occurs. Asin Case 1, if configuration of SL resources within UL resources isnecessary after the BWP switching operation is performed, in order toensure UL transmission of the terminal in the switched BWP after T₁ forBWP switching, a delay time of SL resource configuration (Hereinafter,‘T₂’) may be added.

FIG. 10 is a conceptual diagram illustrating a first exemplaryembodiment of a communication method according to Case 1.

Referring to FIG. 10 , a BWP switching operation from a UL BWP#1 to a ULBWP#2 may be performed, a mapping relationship between the UL BWP#1 andan SL BWP#1 may be configured, and a mapping relationship between the ULBWP#2 and an SL BWP#2 may be configured. The SL BWP#1 may be configuredto be the same as the UL BWP#1, and the SL BWP#2 may be configured to bethe same as the UL BWP#2. When the BWP switching operation from the ULBWP#1 to the UL BWP#2 is performed, a BWP switching operation from theSL BWP#1 to the SL BWP#2 may be automatically performed. Whenconfiguration of SL resources within UL resources is required in theswitched BWP, the configuration of SL resources may be applied after T₂to ensure UL transmission of the terminal in the switched BWP.Alternatively, the configuration of SL resources may be applied after T₁in the switched BWP, but the configuration of SL resources may beignored during T₂ to ensure UL transmission. That is, the terminal mayperform UL transmission during T₂ in the switched BWP.

In case 2, the UL resources and the SL resources may be independentlyconfigured. Since configuration of SL resources within UL resourcesafter BWP switching occurs is unnecessary, additional configuration ofT₂ for configuration of SL resources after BWP switching (e.g., afterT1) may not be required. In the independently-configured UL resourcesand SL resources, the terminal may simultaneously perform UL and SLtransmission operations. In this case, the terminal may simultaneouslyperform a UL transmission operation in the switched UL BWP after BWPswitching (e.g., after T₁) and an SL transmission operation (e.g., PSCCHand/or PSSCH transmission operation) in the SL BWP (e.g., switched BWP).When a sum of a transmission power for the UL transmission and atransmission power for the SL transmission exceeds a maximumtransmission power (e.g., allowable transmission power), a transmissionpower may be preferentially allocated to the UL transmission.Alternatively, transmission power may be preferentially allocatedaccording to the priority of the UL transmission or the SL transmission.The same SCS may be applied in the UL BWP and SL BWP in which thesimultaneous transmission operation is performed.

On the other hand, simultaneous transmission of UL and SL may not bepossible due to capability of the terminal. In this case, in order toensure UL transmission in the switched BWP, SL resources may beconfigured as invalid resources during a delay time (hereinafterreferred to as ‘T₃’) to ensure UL transmission of the terminal after T₁for BWP switching. Alternatively, the UL transmission may be performedpreferentially among the UL transmission and the SL transmission duringT₃.

In Cases 3 and 4, the mapping relationship between UL BWP and SL BWP maynot be configured. Therefore, even when a UL BWP switching occurs, an SLBWP switching operation may not occur. When a numerology of a switchedUL BWP is different from that of an existing SL BWP as in Case 4, the SLBWP is deactivated, so that an additional operation to ensure ULtransmission in the switched UL BWP may be unnecessary. When anumerology of the switched UL BWP is the same as that the existing SLBWP as in Case 3, the existing SL BWP may be maintained in the activestate. In this case, as in Case 2, the terminal supporting simultaneousUL and SL transmission operations may simultaneously perform a ULtransmission operation in the UL BWP and an SL transmission operation(e.g., PSCCH and/or PSSCH transmission operation) in the SL BWP.

When a sum of a transmission power for UL transmission and atransmission power for SL transmission exceeds a maximum transmissionpower (e.g., allowable transmission power), a transmission power may bepreferentially allocated to the UL transmission. Alternatively,transmission power may be preferentially allocated according to thepriority of the UL transmission or the SL transmission. On the otherhand, the simultaneous transmission operation of UL and SL may not bepossible due to the capability of the terminal. In this case, it may benecessary to configure T₃ to ensure the UL transmission in the switchedUL BWP.

FIG. 11 is a conceptual diagram illustrating a first exemplaryembodiment of a communication method according to Case 3.

Referring to FIG. 11 , a BWP switching operation from a UL BWP#1 to a ULBWP#2 may be performed, and a mapping relationship between UL BWP and SLBWP may not be configured. In this case, since a numerology of aswitched UL BWP (i.e., UL BWP#2) is the same as that of an existing SLBWP (i.e., UL BWP#1), the existing SL BWP may not be deactivated. Thatis, the SL BWP may be maintained in the activated state. The terminalmay not simultaneously perform an SL transmission operation in the ULBWP#1 and a UL transmission operation in the UL BWP#2. In this case, inorder to ensure a UL transmission operation of the terminal in theswitched UL BWP (i.e., UL BWP#2), it may be necessary to configure SLresources as invalid resources during T₃ in the UL BWP#1. Alternatively,a priority of UL transmission during T₃ may be configured to be higherthan that of SL transmission. When UL transmission and SL transmissionoccur at the same time after T₃, the terminal may compare the priorityof UL transmission and the priority of SL transmission for eachtransmission, and may perform a transmission having a higher priority(e.g., UL transmission or SL transmission).

The additional delay time (e.g., T₂ or T₃) for ensuring UL transmissionin the UL BWP switched after T₁ for BWP switching may be configuredidentically or differently. The additional delay time may bepreconfigured as a specific value(s). The additional delay time may beconfigured by one or a combination of two or more among systeminformation signaling, cell-specific RRC signaling, UE-specific RRCsignaling, signaling for timer setting, MAC CE signaling, and L1 controlinformation (e.g., DCI or SCI) signaling.

When a current carrier is not an independent SL carrier, some of ULresources may be configured as SL resources. In order to configure SLresources within available UL resources, a bitmap may be repeatedlyapplied within a specific period. A slot mapped to a bit set to 1 in thebitmap may be configured as an SL resource. A plurality of SL resourcepools in the BWP may be configured according to a transmission mode orvarious reasons. When there are a plurality of BWPs (e.g., a pluralityof SL BWPs), a method of configuring SL resource pools for the pluralityof SL BWPs may be required.

In each of the plurality of BWPs, the SL resource pool may be configuredthrough separate signaling. When the SL resource pool is independentlyconfigured in each of the plurality of BWPs through separate signaling,flexible SL resource configuration may be possible according to asituation of each of the plurality of BWPs. Accordingly, resources maybe used efficiently. However, a signaling overhead for configuring theSL resource pools may increase.

Alternatively, a reference BWP may be configured, and SL resource poolconfiguration based on the reference BWP may be applied to another BWP.In this case, the SL resource pool configuration may be the same in theplurality of BWPs. Therefore, a switching operation between the BWPs maybe easily performed. A signaling overhead when the SL resource poolconfigurations are the same may be smaller than a signaling overheadwhen the SL resource pool configurations are different in the pluralityof BWPs.

When the SL resource pool configuration based on the reference BWP isapplied to the plurality of BWPs, and numerologies are different in theplurality of BWPs, the SL resource pool may be configured inconsideration of a ratio among numerologies of the plurality of SLresource pools. For example, when the reference BWP (e.g., BWP#1) has anumerology (e.g., SCS) of 15 kHz, and another BWP (e.g., BWP#2) has anumerology of 30 kHz, a ratio between the numerologies of the BWP#1 andBWP#2 may be 2 (i.e., 30 kHz/15 kHz=2^((μ2-μ1))=2⁽²⁻¹⁾. μ may indicatethe numerology. The value of the ratio of the numerologies (i.e., 2) maybe configured as the number of repetitions for the value of each bit ofthe bitmap, which is configuration information of the SL resource poolof the BWP#1. This operation may be applied to the SL resource poolconfiguration of the BWP#2. In this case, the reference BWP may beconfigured as a BWP having the smallest numerology among the pluralityof BWPs.

FIG. 12 is a conceptual diagram illustrating a first exemplaryembodiment of different BWPs to which the same SL resource poolconfiguration is applied.

Referring to FIG. 12 , a BWP#1 may be a reference BWP, and a bitmap(i.e., first bitmap) for SL resource pool configuration of the BWP#1 maybe ‘00111000011100’. In this case, since a ratio between numerologies ofthe BWP#1 and a BWP#2 is 2, a bitmap (i.e., second bitmap) configured as‘0000111111000000001111110000’ may be generated by repeating therespective bit values of the bitmap (i.e., first bitmap) twice. An SLresource pool of the BWP#2 may be configured based on the correspondingbitmap (i.e., ‘0000111111000000001111110000’).

According to switching, activation, and/or deactivation operations ofthe BWP(s), resources may be efficiently used in various situations. Byconfiguring a plurality of SL resource pools within one BWP, resourcesmay be used efficiently. SL resource pool(s) used fortransmission/reception operations in sidelink communication may beconfigured for each terminal. The SL resource pool used for sidelinkdata transmission may be a TX resource pool, and one or more TX resourcepools may be configured. The SL resource pool used for sidelink datareception may be an RX resource pool, and one or more RX resource poolsmay be configured.

Since an RX resource pool for adjacent cells and an RX resource pool forout-of-coverage terminal(s) are required as well as the RX resource poolfor one cell, the number of RX resource pools may be configured to behigher than the number of TX resource pools. A modulation and codingscheme (MCS) table and/or a demodulation-reference signal (DM-RS)pattern for each of the SL resource pools (e.g., TX resource pool, RXresource pool) may be configured. In each of the SL resource pools, aseparate MCS table and/or DM-RS pattern may be configured according to achannel state and/or a service requirement. A suitable SL resource poolsuitable for sidelink transmission may be configured, and a resourceregion for PSCCH and/or PSSCH transmission may be scheduled within theSL resource pool. A transmitting terminal may perform PSCCH and/or PSSCHtransmission in the scheduled resource region.

A plurality of SL resource pools may be configured, and a specific SLresource pool(s) within the plurality of SL resource pools may bedynamically selected for sidelink transmission. In this case, a resourceregion of a PSCCH and/or PSSCH may be scheduled within the selected SLresource pool. When there are a plurality of SL resource pools,ambiguity may occur with respect to the scheduling information of thePSCCH and/or PSSCH.

The size of scheduling information of the time and frequency resourceregions may vary depending on the number of slots and/or the number ofsubchannels in which sidelink data can be transmitted/received. Theabove-described parameters (e.g., size and/or number) may be differentfor each SL resource pool. A position of the available slot(s) and/or afrequency start position of the subchannel(s) may be different for eachSL resource pool. Even when the scheduling information has the samesize, the position of the actual resource region indicated by thecorresponding scheduling information may be different in the respectiveSL resource pools. A plurality of SL resource pools may overlap in thetime domain and/or the frequency domain. In this case, if the SLresource pool indicated by the scheduling information of the PSCCHand/or PSSCH is not explicitly known, the above-described problem (e.g.,ambiguity problem) may occur.

When the PSCCH and/or PSSCH resource region is scheduled by DCI (e.g.,DCI format 3_0), the DCI may further include information indicating anindex of the SL resource pool in order to solve the aforementionedambiguity problem. The SL resource pool indicated by the DCI may be anSL resource pool to which sidelink scheduling information included inthe DCI is applied. The transmitting terminal may receive the DCI fromthe base station, identify the index of the SL resource pool included inthe DCI, and apply the scheduling information of the time and frequencyresource region included in the DCI to the identified SL resource pool,thereby identifying the position of the time and frequency resourceregion to be used for PSCCH and/or PSSCH transmission. The transmittingterminal may perform PSCCH and/or PSSCH transmission using theidentified time and frequency resource region. In this case, thetransmitting terminal may transmit SCI including information on theresource region scheduled for sidelink communication to the receivingterminal. Even in this case, an ambiguity problem may occur between theplurality of SL resource pools in the receiving terminal. To solve thisproblem, the SCI may further include information indicating the index ofthe SL resource pool. The SL resource pool indicated by the SCI may bean SL resource pool to which the sidelink scheduling informationincluded in the corresponding SCI is applied.

For example, ceiling(log 2(N_(pools))) bits may be added to the SCI(e.g., a first stage SCI (e.g., SCI format 1-A) and/or a second stageSCI), and the added bit(s) may be used to indicate the index of the SLresource pool. N_(pools) may indicate the number of TX resource pools.When configuration of up to 8 TX resource pools is possible, the maximumsize of bits added to the SCI may be 3 bits. When the maximum number ofconfigurable TX resource pools increases, the maximum size of bits addedto the SCI may also increase.

The information included in the DCI and/or SCI may indicate the index ofthe SL resource pool (e.g., TX resource pool). The transmitting terminalmay transmit sidelink data through the TX resource pool configured bythe DCI and/or SCI. The receiving terminal may receive the sidelink datathrough the RX resource pool. Even when the SL resource pool indicatedby the information included in the DCI and/or SCI is not distinguishedbetween the TX resource pool or the RX resource pool, in order toprevent the problem of ambiguity between the TX resource pool of thetransmitting terminal and the RX resource pool of the receiving terminalfrom occurring, a mapping relationship between TX resource pool and RXresource pool may be configured. For example, a time and frequencyresource region of the TX resource pool #0 may be configured to be thesame as a time and frequency resource region of the RX resource pool #0.When desiring to transmit sidelink data in the TX resource pool #0, thetransmitting terminal may transmit SCI (e.g., first stage SCI and/orsecond stage SCI) including information indicating the TX resource pool#0, and transmit the sidelink data in the TX resource pool #0. Thereceiving terminal may receive the SCI from the transmitting terminal,and may identify an index of the TX resource pool indicated by the SCI.When the SCI indicates the TX resource pool #0, the receiving terminalmay receive the sidelink data in the RX resource pool #0 mapped to theTX resource pool #0 (e.g., the time and frequency resource region in theRX resource pool #0, that is indicated by the scheduling informationincluded in the SCI) from the transmitting terminal. When the TXresource pool and the RX resource pool having the same index areconfigured (e.g., implicitly configured) in the same time and frequencyresource region, the ambiguity problem in the scheduling signaling fortransmission of sidelink data between the transmitting terminal and thereceiving terminal may be solved.

By configuring the TX resource pool and the RX resource pool in the sametime and frequency resource region within the same cell, the ambiguityproblem between the transmitting terminal and the receiving terminal maybe solved. However, it may be difficult to apply the above-describedmethod(s) to the RX resource pool for receiving data from adjacentcell(s) and/or data from out-of-coverage terminal(s).

FIG. 13 is a conceptual diagram illustrating a first exemplaryembodiment of a method of configuring an SL resource pool in adjacentcell(s) and out-of-coverage terminal(s).

Referring to FIG. 13 , 5 RX resource pools and 2 TX resource pools maybe configured in a cell #0. In the cell #0, an RX resource pool #0 maybe associated (e.g., mapped) with a TX resource pool #0, and an RXresource pool #1 may be associated with a TX resource pool #1. An RXresource pool #2 of the cell #0 may be associated with a TX resourcepool #0 of a cell #1 that is an adjacent cell, and an RX resource pool#3 of the cell #0 may be associated with a TX resource pool #1 of thecell #1. An RX resource pool #4 of the cell #0 may be associated with aTX resource pool #0 of an out-of-coverage terminal.

A transmitting terminal of the cell #1 may transmit sidelink datathrough the TX resource pool #1 of the cell #1. In this case, an SLresource pool index included in SCI transmitted by the transmittingterminal of the cell #1 may be set to 1. The RX resource pool #1 of thecell #0 may be associated with the TX resource pool #1 of the cell #0,and an RX resource pool associated with the TX resource pool #1 of thecell #1 may be the RX resource pool #3 of the cell #0. Accordingly, whenthe transmitting terminal of the cell #1 sets the SL resource pool indexbased on the TX resource pool, an index of the RX resource poolinterpreted based on the SL resource pool index included in the SCI maybe different from an index of an RX resource pool used for actuallyreceiving sidelink data.

In order to solve the above-described ambiguity problem, a mappingrelationship between TX resource pool and RX resource pool may beconfigured explicitly. For example, in a step of configuring an SLresource pool for sidelink communication between a terminal belonging tothe cell #0 and a terminal belonging to the cell #1, configurationinformation indicating that the TX resource pool #1 of the cell #1 ismapped to the RX resource pool #3 of the cell #0 may begenerated/transmitted. The above-described configuration information maybe indicated by one or a combination of two or more among systeminformation signaling, cell-specific RRC signaling, UE-specific RRCsignaling, MAC CE signaling, and L1 control information signaling. Forexample, configuration parameter(s) of the resource pool (e.g., SLresource pool) may include information of SL resource pool(s) ofadjacent cell(s), TDD configuration information of adjacent cell(s),synchronization-related information of adjacent cell(s), and/orindex(es) of SL resource pool(s) (e.g., TX resource pool(s) or RXresource pool(s)) mapped to SL resource pool(s) of adjacent cell(s).

Even when configuration information indicating a mapping relationshipbetween TX resource pool and RX resource pool is explicitly signaled, itmay be necessary to clearly distinguish TX resource pool index(es)detectable in a specific RX resource pool between cells. For example, inthe exemplary embodiment shown in FIG. 13 , a mapping relationshipbetween the RX resource pool #2 of the cell #0 and the TX resource pool#0 of the cell #1 may be configured, and a resource region of the RXresource pool #2 may overlap with a resource region of the RX resourcepool #0 of the cell #0, that is mapped to the TX resource pool #0 of thecell #0. In this case, when ‘TX resource pool index=0’ is detected inSCI received in the overlapped resource region, it may be difficult forthe receiving terminal to identify whether received sidelink data issidelink data transmitted by a terminal of the cell #1 or sidelink datatransmitted by a terminal of the cell #0.

Therefore, when an RX resource pool is mapped to (e.g., associated with)a TX resource pool of adjacent cell(s), it may be preferable toconfigure such that a TX resource pool index identical to a TX resourcepool index of adjacent cell(s) is not received in the corresponding RXresource pool from the same cell. A resource region of an RX resourcepool (e.g., RX resource pool #2 and/or #3) associated with a TX resourcepool of adjacent cell(s) may be configured so as not to overlap with aresource region of an RX resource pool (e.g., RX resource pool #0 and/or#1) associated with a TX resource pool of the same cell, thereby solvingthe above-described problem.

When configuration information of a mapping relationship between TXresource pool and RX resource pool is signaled, interpretation of an SLresource pool index may be performed according to the mappingrelationship. Even when a mapping relationship between TX resource pooland RX resource pool is not separately configured, the receivingterminal may always recognize sidelink data received in thecorresponding RX resource pool as sidelink data from an adjacent cell.In this case, the receiving terminal may ignore an SL resource poolindex indicated by a control channel (e.g., DCI and/or SCI), and mayreceive sidelink data in consideration of only RX resource poolconfiguration.

Alternatively, a mapping relationship between SL resource pools may beconfigured in consideration of preconfigured constraints. For example,up to 8 TX resource pools may be configurable, and an index of each ofthe 8 TX resource pools may be set to one value from 0 to 7. Inaddition, a maximum of 16 RX resource pools may be configurable, and anindex of each of the 16 RX resource pools may be set to one value from 0to 15. In this case, RX resource pool indexes #0 to #7 may be mapped toTX resource pools of the same cell. RX resource pool indexes #8 to #15may be recognized as corresponding to RX resource pools of adjacentcell(s), and a TX resource pool index indicated by control informationdetected in the corresponding RX resource pool may be interpreted as aTX resource pool index of a TX resource pool of an adjacent cellaccording to a preconfigured mapping relationship. The receivingterminal may obtain scheduling information and/or sidelink data based onthe above-described interpretation.

The number of configurable TX resource pools and RX resource pools maybe configured within a maximum number according to a situation of thesystem. RX resource pools other than RX resource pools corresponding toTX resource pools configured within the same cell may be configured asRX resource pools for adjacent cell(s) and/or for special purpose(s). ATX resource pool indicated by control information detected in thecorresponding RX resource pool may be interpreted regardless of a TXresource pool index of the same cell. That is, a TX resource poolindicated by the control information may be interpreted as a TX resourcepool for adjacent cell(s) and/or special purpose(s). The TX resourcepool indicated by the control information may not be considered in astep of receiving sidelink data.

Alternatively, an SL resource pool of adjacent cell(s) and/or an SLresource pool for sidelink communication of out-of-coverage terminal(s)may be configured independently (or separately) from other resourcepools. In addition, a common SL resource pool may be configured, andsidelink communication may be performed in the common SL resource pool.In this case, a method(s) indicating whether sidelink communication inthe common SL resource pool is sidelink communication of adjacentcell(s) or sidelink communication of out-of-coverage terminal(s) may beused.

FIG. 14 is a conceptual diagram illustrating a second exemplaryembodiment of a method of configuring an SL resource pool in adjacentcell(s) and out-of-coverage terminal(s).

Referring to FIG. 14 , a specific SL resource pool (e.g., SL resourcepool #X) for sidelink communication of adjacent cell(s) or sidelinkcommunication of out-of-coverage terminal(s) may be configured. Thespecific SL resource pool may be configured in common for both adjacentcell(s) and out-of-coverage terminal(s). The specific SL resource poolmay refer to a common SL resource pool. When a common SL resource pool(e.g., SL resource pool #X) is configured for all terminals performingsidelink communication, configuration of a mapping relationship betweenTX resource pool and RX resource pool in adjacent cell(s) or a mappingrelationship between TX resource pool and RX resource pool inout-of-coverage terminal(s) may not be required. That is, sidelinkcommunication may be performed without signaling configurationinformation of the mapping relationship between TX resource pool and RXresource pool.

The common SL resource pool may be configured within the cell separately(or independently) from the SL resource pool for sidelink communicationand/or the SL resource pool for other purpose(s). A resource region ofthe common SL resource pool may be configured so as not to overlap witha resource region of the SL resource pool for sidelink communicationand/or the SL resource pool for other purpose(s). In this case, evenwhen sidelink communication is scheduled without an indication of an SLresource pool index, sidelink data detected in the common SL resourcepool may be recognized as sidelink data transmitted by a terminal of anadjacent cell or an out-of-coverage terminal.

In the exemplary embodiment shown in FIG. 14 , the common SL resourcepool may be configured for both a terminal of an adjacent cell and anout-of-coverage terminal. The common SL resource pool for sidelinkcommunication of adjacent cell(s) (e.g., SL resource pool #X) and aseparate common SL resource pool for sidelink communication ofout-of-coverage terminal(s) (e.g., SL resource pool #Y) may berespectively configured. The common SL resource pool may bepreconfigured. Alternatively, configuration information of the common SLresource pool may be transmitted using one or a combination of two ormore among system information signaling, cell-specific RRC signaling,UE-specific RRC signaling, S-SSB signaling, MAC CE signaling, and L1control information signaling. An out-of-coverage terminal may identifythe common SL resource pool by receiving an S-SSB. That is, an S-SSB maybe used to indicate the common SL resource pool.

The exemplary embodiments of the present disclosure may be implementedas program instructions executable by a variety of computers andrecorded on a computer readable medium. The computer readable medium mayinclude a program instruction, a data file, a data structure, or acombination thereof. The program instructions recorded on the computerreadable medium may be designed and configured specifically for thepresent disclosure or can be publicly known and available to those whoare skilled in the field of computer software.

Examples of the computer readable medium may include a hardware devicesuch as ROM, RAM, and flash memory, which are specifically configured tostore and execute the program instructions. Examples of the programinstructions include machine codes made by, for example, a compiler, aswell as high-level language codes executable by a computer, using aninterpreter. The above exemplary hardware device can be configured tooperate as at least one software module in order to perform theembodiments of the present disclosure, and vice versa.

While the embodiments of the present disclosure and their advantageshave been described in detail, it should be understood that variouschanges, substitutions and alterations may be made herein withoutdeparting from the scope of the present disclosure.

What is claimed is:
 1. An operation method of a first terminal in acommunication system, the operation method comprising: receiving, from abase station, configuration information of a mapping relationshipbetween an uplink (UL) bandwidth part (BWP) and a sidelink (SL) BWP;when a UL switching operation for the UL BWP is performed, performing anSL switching operation for the SL BWP mapped to the UL BWP based on themapping relationship without separate signaling indicating execution ofthe SL switching operation; and performing sidelink transmission with asecond terminal in a switched SL BWP, wherein an SL resource isconfigured after a preconfigured time from a completion time of the ULswitching operation within the switched UL BWP.
 2. The operation methodaccording to claim 1, wherein the configuration information is includedin system information or a terminal-specific radio resource control(RRC) message transmitted from the base station.
 3. The operation methodaccording to claim 1, wherein a same subcarrier spacing (SCS) is appliedto the UL BWP and the SL BWP having the mapping relationship.
 4. Theoperation method according to claim 1, wherein when an SL resource isconfigured independently of a UL resource, the sidelink transmission inthe switched SL BWP and uplink transmission in a switched UL BWP aresimultaneously performed or the uplink transmission is prioritized fromthe completion time of the UL switching operation to a preconfiguredtime to ensure the uplink transmission.
 5. The operation methodaccording to claim 1, further comprising, when an activation operationfor the UL BWP is performed, performing an activation operation for theSL BWP mapped to the UL BWP based on the mapping relationship.
 6. Theoperation method according to claim 1, further comprising, when adeactivation operation for the UL BWP is performed, performing adeactivation operation for the SL BWP mapped to the UL BWP based on themapping relationship.
 7. The operation method according to claim 1,wherein an SL resource pool is configured based on a reference BWP, andwhen a first numerology of the reference BWP is different from a secondnumerology of the SL BWP, the SL resource pool is applied to the SL BWPin consideration of a ratio between the first numerology and the secondnumerology.
 8. An operation method of a base station in a communicationsystem, the operation method comprising: configuring a mappingrelationship between an uplink (UL) bandwidth part (BWP) and a sidelink(SL) BWP; transmitting configuration information of the mappingrelationship to a terminal; performing a UL switching operation for theUL BWP; and performing uplink transmission with the terminal in aswitched UL BWP, wherein an SL switching operation for the SL BWP istriggered by performing the UL switching operation, and an SL resourceis configured from a completion time of the UL switching operationwithin a switched UL BWP, and the SL resource configured until apreconfigured time from the completion time of the UL switchingoperation is ignored.
 9. The operation method according to claim 8,wherein the configuration information is included in system informationor a terminal-specific radio resource control (RRC) message transmittedfrom the base station.
 10. The operation method according to claim 8,wherein a same subcarrier spacing (SCS) is applied to the UL BWP and theSL BWP having the mapping relationship.
 11. An operation method of afirst terminal in a communication system, the operation methodcomprising: receiving, from a base station, configuration information ofa mapping relationship between an uplink (UL) bandwidth part (BWP) and asidelink (SL) BWP; when a UL switching operation for the UL BWP isperformed, performing an SL switching operation for the SL BWP mapped tothe UL BWP based on the mapping relationship without separate signalingindicating execution of the SL switching operation; and performingsidelink transmission with a second terminal in a switched SL BWP,wherein an SL resource pool is configured based on a reference BWP, andwhen a first numerology of the reference BWP is different from a secondnumerology of the SL BWP, the SL resource pool is applied to the SL BWPin consideration of a ratio between the first numerology and the secondnumerology.